Data commit

Task/Digital-root/Jq/digital-root-1.jq

@@ -0,0 +1,20 @@
+def do_until(condition; next):
+  def u: if condition then . else (next|u) end;
+  u;
+
+# n may be a decimal number or a string representing a decimal number
+def digital_root(n):
+  # string-only version
+  def dr:
+    # state: [mdr, persist]
+    do_until( .[0] | length == 1;
+              [ (.[0] | explode | map(.-48) | add | tostring), .[1] + 1 ]
+              );
+  [n|tostring, 0] | dr | .[0] |= tonumber;
+
+def neatly:
+  . as $in
+  | range(0;length)
+  | "\(.): \($in[.])";
+
+def rjust(n): tostring | (n-length)*" " + .;

Task/Digital-root/Jq/digital-root-2.jq

@@ -0,0 +1,8 @@
+(
+ "          i : [DR, P]",
+ (961038, 923594037444, 670033, 448944221089
+ ) as $i
+   | "\($i|rjust(12)): \(digital_root($i))"
+),
+ "",
+ "digital_root(\"1\" * 100000) => \(digital_root( "1" * 100000))"

Task/Digital-root/Jq/digital-root-3.jq

@@ -0,0 +1,9 @@
+$ jq -M -n -r -c -f Digital_root.jq
+
+          i : [DR, P]
+      961038: [9,2]
+923594037444: [9,2]
+      670033: [1,3]
+448944221089: [1,3]
+
+digital_root("1" * 100000) => [1,2]